mhonarc-users

Re: Footer lost when any attachement is present

2003-02-05 13:30:19
On February 5, 2003 at 18:34, Ruben Gaspar wrote:

I have seen that using mhonarc on mail (coming from a distribution list 
with a footer definition) which also contains an attachment, this footer 
is lost. Looking at the archive I can see that the mail and footer is 
properly archived, in this order:

Mail body
Attachement
Footer

Mohnarc is not rendering the last one. Is there a possibility to avoid 
this behaviour (my Mhonarc version is: MHonArc v2.4.5 (Perl 5.00503)) .

No.

I'm not sure how good your technical knowledge is, but I will
try to explain:

A message with an attachment is MIME encoded, and MHonArc is MIME-aware.
A message of the type you mention would be formated like the following:

    To: ...
    Subject: ...
    Content-Type: multipart/mixed; boundary="XXX"

    --XXX

    This is the main body text that you see.
    ...

    --XXX
    Content-Type: application/octet-stream
    Content-Transfer-Encoding: base64
    Content-Disposition: attachment; filename="somfile"

    [base64 encoded data of attachment here...]

    --XXX--

    [list footer here...]

According to the MIME specs, everything before the first boundary
(i.e. the first "--XXX") is ignored by a MIME-aware client.  Also,
everything after the final boundary "--XXX--" is to be ignored.

The problem is that the list software blindly tacks on the message
footer and does not check if the message is a multipart message.
If the list software wanted to be sure that the footer would get
rendered, it needs to detect then main content-type of the message
and potentially restructure the message.  For a multipart message,
it will need to insert the footer as the final part.  If the
content-type is a non-text type, it would need to convert the
message into a multipart message to avoid potentially corrupted
the body data.

Actually thinking about it a little more, to avoid problems with
encrypted/signed messages, if the main content-type is not a simple
text type, it would need to convert the message into a multipart type
with the first part being the contents of the message and the last
part being the footer.  And, I am not sure that this can be
done properly without invalidating encrypted/signed messages.

In general, I think it is better for list software to utilize
the List-* headers as described in RFC 2369 vs appending data
to messages bodies for the technical reasons highlighted above.

--ewh

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